The invention relates to a method for making lawn mower blades and, in particular, for forming the cutting edge thereon.
A significant portion of the cost of manufacturing lawn mower blades has heretofore been spent on providing the necessary cutting edges on the blade.
The cutting edges have been produced by milling, grinding, or broaching.
Variations of these methods have also been used.
U.S. Pat. No. 5,077,961 shows a method for forming a cutting edge on a mower blade by first embossing a beveled edge on the blade. In the process, a portion of the blade is extruded 14 beyond this bevel. The extruded portion is then ground off.
Similarly, U.S. Pat. No. 4,198,803 coins a beveled edge on a harvesting machine's knife and then grinds off the portion extending out of the knife's plane.
The cutting edges of both of these patents still require that an expensive grinding process be used to produce the finished edge.